.box {
    width: 1000px;
    height: 200px;
    margin: 100px auto;
    border: 1px solid #000;

    overflow: hidden;
    ul {
        margin: 0;
        padding: 0;
        display: flex;
        list-style: none;
    animation: cha 15s infinite linear ;
        img {
            width: 400px;
            height: 200px;
        }
    }
}

@keyframes cha {
    0%{
        transform: translate(0);
    }
    100%{
        transform: translate(-1400px);
    }
}